A strong association between endometrial cancer and estrogen replacement therapy, with a 4-8 fold relative risk, has been demonstrated in a substantial number of case-control studies, starting in 1975. In New York State the incidence of endometrial cancer rose rapidly from 1970 to 1975, then began to decline. National and local figures on estrogen sales suggest that they peaked in 1976, and then dropped off sharply. We intend to carry out retrospective surveys of practicing physicians and of women ages 40-59 in a 7 county study area and a similiar control area to learn which educational and regulatory approaches were most important in bringing about this decrease in estrogen use. The women's survey will include questions relating to the epidemiology of menopause, history of estrogen replacement therapy and recognition of symptoms of endometrial cancer. A survey of pharmacies in both areas will be conducted to provide objective data on current estrogen prescribing practices. A professional educational campaign is planned in the second year of the study to promote a careful consideration of the risks and benefits of estrogen use for menopausal women and what alternate therapies are available. Secondary prevention of endometrial cancer by regular follow up of high risk women will stressed. In the third year post-program surveys will be conducted in the study and control counties to evaluate the impact of the educational program on physicians' knowledge, prescribing patterns and follow-up practices.